Rail-lapping machine



Nov. 8, 1960 M. o. MAHONEY 2,958,985

RAIL-MAPPING MACHINE Filed Oct. 18, 1956 2 Sheets-Sheet 1- fiil laa 72 58 wmmswxxnmma ll I11. J8 INVENTOR' Nov. 8, 1960 M. D. MAHONEY RAIL-LAPPING museums 2 Sheets-Sheet 2 Filed Oct. 18, 1956 United States Patent O RAlL-LAPPING MACHINE Marvin D. Mahoney, Hagerstown, Ind., assignor to Perfect Circle Corporation, Hagerstown, Ind., a corporation of Indiana Filed Oct. 18, 1956, Ser. No. 616,770

3 Claims. (Cl. 51-59) This invention relates in general to the fabrication of piston ring elements, and more particularly to a machine for lapping the peripheral edge of rail stock used in oil rings for pistons. Several kinds of oil rings currently being used on the pistons of internal combustion engines are built-up structures having a pair of circular rails spaced from each other in the piston oil ring groove by appropriate spacer means. Such rails are generally washer-like fiat metallic elements that are adapted to project from the oil ring groove so that their pheripheral edges press against the wall of the cylinder. These rails are usually fabricated from an elongated strip of sheet metal having a radius or curvature formed on the edges thereof. The strip is bent edgewise into circular form and since the strip is usually of sufficient length to form a number of rings, the edgewise bending results in a closed cylindrical coil. The coil is then cut longitudinally so that each turn of the coil becomes a complete rail, the outer peripheral edge of which is curved in cross section.

The outer peripheral edge of such rails is frequently plated, such as with a chrome plate, to improve wearing qualities. The plating operation may be performed either before a coil of rail stock has been severed into individual rails or thereafter. The plating operation often produces pimples or other objectionable surface irregularities, and the rail stock, either before or after severing into individual rails, undergoes a finishing opera tion which, among other things, effects the removal of such irregularities.

vHeretofore, chrome plated rails of the character just described have usually been finished by either of two methods. One of these methods efiects merely the removal of surface irregularities such as pimples by subjecting the rail stock to a buffing operation. Such buffing consists of placing the rail stock on an arbor, and subjecting it to the action of a rotary cloth wheel impregnated with an abrasive. This method does very little toward reducing the rails to a predetermined form and size.

In the other method heretofore employed, the irregularities in the chrome are positively removed and at the same time the rails are reduced to a predetermined form and size by a face-lapping operation. In this instance, the rail stock, together with liquid abrasive, is placed in a cylindrical pot having the same internal shape as the external shape of the finished rails, and the rail stock is moved back and forth therein. With this method, the pimples and irregularities on the periphery of the rail stock are removed and at the same time the rail stock is given a desired shape.

The general object of the present invention is to proyide a novel machine for lapping rail stock.

. Another object is to provide a novel machine for lapping rail stock which finishes the stock to an extent lying between that accomplished by the methods outlined above, that is, which removes irregularities on the periph- Patented Nov. 8, 1960 l-ni eral surface of the rails and at the same time improves to some extent their external shape.

Another object is to provide a rail lapping machine which is simple in construction and requires very little attention during operation so that one operator may take care of a number of such machines.

Other objects and advantages of the invention will become apparent from the subsequent description taken in conjunction with the accompanying drawings wherein:

Fig. l is a perspective view of a machine embodying the features of the invention;

Fig. 2 is a front elevational view of the machine shown inFig. 1;

Fig. 3 is a top plan view of the machine shown in Fig. 1;

Fig. 4 is an end elevational view of the machine shown in Fig. 1, and

Fig. 5 is a fragmentary perspective view of a typical rail, showing a cross section thereof.

The term rail stock, is used herein to mean either a coil of plated rail material, which has not yet been cut into individual rails, or a stack of individual rails, such as that resulting when a coil is longitudinally cut. The machine provided effects lapping of the rail stock and is adapted to accommodate either of the types of rail stock referred to above.

In Fig. 5 a fragment of piston ring rail stock of the type herein contemplated is shown. The rail stock has two fiat, parallel, opposing sides 68 and 69, and the inner and outer edges of the rail stock are curved in a crosssection, as at 71 and 72, with the outer peripheral edge 71 chrome plated, as previously described.

A machine embodying the invention includes supporting structure that resiliently supports and rotates the rail stock. It also includes a lapping-shoe positioned to contact the exposed generally cylindrical surface of the rail stock, the shoe being pressed into engagement with the rail stock and reciprocated longitudinally relative thereto as the rail stock is rotated and lapping proceeds. A liquid abrasive may be used to enhance the lapping process and the machine permits the lapping in one operation all of the turns of a coil of substantial length or a stack composed of a large number of individual rails.

Referring to the drawings, the machine illustrated includes a base 10 on which is mounted a rotatably driven spindle structure 11 that is adapted to support and rotatably drive the rail stock indicated at 12. The spindle structure .11 preferably is mounted on a horizontal axis, and a shoe 13 is movably mounted over the spindle structure and is pressed into engagement with the peripheral surface of the rail stock 12. The shoe is also reciprocable longitudinally along the spindle structure 11.

The spindle structure 11 is provided with a resilient surface portion for directly supporting and rotating the rail stock. Thus, the spindle structure comprises a shaft 14 having a sleeve 16 mounted on one end thereof, the sleeve 16 being made of rubber or rubber like material. The sleeve 16 being of such material, the friction between the sleeve and the rail stock 12 is sufficient to effect rotation of the rail stock when the shoe 13 is in lapping engagement against the peripheral surface thereof, and the sleeve 16 is yieldable, to compensate for any minor width variations that may exist between the individual turns of the rail stock. The sleeve 16 is dimensioned so that its outer diameter is somewhat less than the inner diameter of the rail stock to be mounted thereon. Thus, the rail stock contacts only the top portion of the sleeve. The sleeve 16 may be any convenient length commensurate with the amount of rail stock to be lapped in any single operation.

In order that the rail stock may be conveniently loaded on the machine, spindle structure 11 is mounted in overhanging relation to the base so that one end is free and unobstructed. Its shaft 14 is rotatably supported by a pair of pillow blocks 17 spaced from each other and secured to the base 10. A portion of the shaft 14 projects from the pillow blocks 17 through an upright shield 18 and carries the sleeve 16. The shield 18 is secured to the base 10 and serves as an abutment for preventing rail stock positioned on the sleeve from traveling along the spindle out of contact with the shoe during the finishing opration and shields the pillow blocks from possible splashing of the abrasive.

The sleeve 16 is secured to the shaft 14 and extends therealong substantially from the shield 18 to a collar 19 positioned on the shaft at the free end of the spindle. The collar 19 is a washer like element, the diameter of which is larger than the outer diameter of the sleeve 16, yet is smaller than the inner diameter of the rail stock. Thus, the collar 19 holds the sleeve 16 on the shaft and also provides a shoulder for preventing the rail stock from being urged off the free end of the spindle during the finishing operation. It is also small enough so that the coil of stock can be moved over it during loading or unloading of the machine. The collar 19 is held in abutment against the end of the sleeve 16 by a nut 21 threaded on the end of the shaft. To rotatably drive the spindle structure 11, the present machine is shown as having a pulley 22 mounted on the end of the shaft 14 opposite the sleeve 16. A belt 23 connects the pulley 22 to an appropriate drive means (not shown), such as a motor. Control of the drive means is effected by an appropriate controller, such as an electric switch 25.

The lapping shoe 13 is an elongated rectangular member that extends longitudinally approximately the full length of the sleeve 16, and is positioned above the sleeve to be pressed into contact with the peripheral surface of the rail stock 12 carried on the sleeve. Shoe 13 has a concave longitudinally extending lapping surface 24, the curvature of which closely approaches the curvature of a finished rail. For supplying an abrasive to the surface of the rail stock, the shoe 13 may be provided with an opening 26, through which liquid abrasive may be introduced, and a longitudinally extending channel 27 intersects the opening 26 and extends the full length of the shoe in its concave surface 24, for carrying the abrasive therealong.

The shoe 13 is mounted on the machine so that it is self-aligning with the peripheral surface of the rail stock upon being moved into contact therewith and reciprocated therealong. In order to permit such self-aligning movement of the shoe 13, the latter in the present instance is mounted on one end of a movable arm 28 by a universal joint connector 29, such as a common ball joint connector. At its end opposite the shoe 13, arm 28 is movably secured by a similar universal joint connector 31 to the top of a support member or post 32. The post 32 is, in turn, rigidly mounted on the base 10 and supports the end of the arm 28 above the base so that the arm will be substantially horizontal when the lapping shoe 13 is in rubbing contact with the rail stock.

To press the shoe 13 into rubbing contact with the rail stock, the instant machine includes an air cylinder 33 for this purpose. The air cylinder 33 is swingably suspended above the arm 28 and is carried by a rigid upright rectangular frame structure, shown generally at 34. The frame structure 34 comprises a pair of upright leg members 36 that are fastened to the base 10 on opposite sides of the arm 28 and a top member 37 extending horizontally therebetween. For swingably supporting the air cylin der 33, the frame 34 is provided with a rectangular block 38 having trunnions 39 on the opposite ends thereof. The block 38 extends longitudinally between the upright members 36 near the top of the frame structure 34, with its trunnions 39 journaled respectively in the leg members 36. The" upper end of the air cylinder 33 is pivotally secured to block 38 by a pin 41, the longitudinal axis of the pin 41 extending generally parallel to the longitudinal axis of the arm 28 to permit the air cylinder to swing from side to side with the arm as the shoe 13 reciprocates. A piston rod 42, actuated by the air cylinder 33, extends downwardly therefrom and is connected to the arm 28 by a longitudinally adjustable sleeve 43 and a pin 44. The pin 44 extends parallel to the arm 28 through a yoke member 46 thereon and an eye 47 secured to the sleeve 43 to provide a pivotal connection therebetween. Thus, the air cylinder 33 is swingably suspended between the top of frame structure 34 and the arm 28 so that it can press the latter, together with the shoe 13, downwardly and at the same time is swingable with the arm 28 as the shoe 13 is reciprocated. The air cylinder 33 affords substantial flexibility with reference to the amount of pressure applied to the rail stock, and after the lapping of the railstock has been accomplished, can be actuated to raise the shoe 13 from the rail stock so that the latter may be removed from the spindle.

The air cylinder 33 is actuated by compressed air carried thereto by a pair of hoses 48, the air being controlled by a valve 49. In this instance, the valve 49 is manually manipulated by a handle 51 thereon and selectively effects raising and lowering of the shoe in response to an appropriate movement of the handle. The valve 49 is carried by a bracket 52 secured to one of the legs 36 of the frame structure.

The machine is also provided with means for adjustably limiting the extent of upward travel of the arm 28. In the preferred form of the machine, this means comprises an additional rectangular frame structure 53 positioned intermediate the shoe 13 and the frame structure 34. The frame structure 53 has a pair of vertical legs 54 that are secured to the base 10 and are positioned on opposite sides of the arm 28, and a top member 56 connects the legs 54. The top member 56 is positioned sufliciently above the arm 28 to permit adequate upward movement of the shoe 13, but is provided with a bolt 57 that projects vertically downwardly therethrough, to act as an adjustable abutment against which the arm 28 is stopped when the shoe has been raised to adequately clear the rail stock.

The relative longitudinal reciprocation between the spindle 11 and the shoe 13, previously mentioned, is effected in order that wear of the lapping surface 24 will be equally distributed over the length of the shoe. In the instant machine the shoe is reciprocated by a drive means preferably connected to the shaft 14. Thus, a worm 58 is mounted on the shaft 14 to rotate therewith, and is positioned thereon between the pillow blocks 17. A worm wheel 59 cooperates with the worm 58 to effect rotation of a second shaft 61, the worm wheel 59 being secured to one end thereof. The shaft 61 is journaled, intermediate its ends, in another pair of pillow blocks 63, the axis of the shaft 61 extending generally horizontally and perpendicularly to the axis of the shaft 14.

The reciprocatory motion of the arm 28 is efiected by an eccentric 62 carried on the rear end of the shaft 61, and a connecting rod, indicating generally at 64, provided with a bearing portion 66 is secured around the eccentric 62. The connecting rod 64 extends substantially horizontally toward the arm 28, and is pivotally connected thereto by a pin 67. To adjust the position of the range of movement of the shoe, the connecting rod 64 is adjustable as to length. .Thus, the connecting rod 64, comprises a pair of end members 68, one provided with the bearing portion 66 and the other fitting over the pin 67. The end members 68 are adjustably threaded into opposite ends of a sleeve 69 and are adapted to be locked in adjusted position by lock nuts 70.

To accomplish the lapping operation, the rail stock 12 is mounted on the spindle 11 as shown in the drawings, and rotation of the spindle 11 is started. As the spindle 11 rotates, the shoe 13 reciprocates longitudinally therealong by virtue of the connecting drive structure. Air is then admitted to the cylinder 33 for pressing the shoe 13 into lapping engagement with the peripheral surface of the rail stock. Inasmuch as the pressure of the shoe 13 on the periphery of the rail stock forces the rail stock into tight contact with the rotating rubber sleeve 16, the rail stock is rotated thereby, and because of the yieldable nature of the sleeve 16, the reciprocating shoe contacts and laps the edge of each turn of the rail stock, notwithstanding the fact that minor variations in their width may exist. Thus, the peripheral edge of each turn of the rail stock is contacted by the shoe 13, and the rail stock is uniformly lapped to the desired condition. During the lapping operation a liquid abrasive may be manually applied to the surface of the rail stock or may be fed thereto through the opening 26.

It is thus seen that the present invention provides a novel machine for lapping the peripheral edges of rail stock, which machine removes any roughness thereon and improves to some extent the external shape of the rails. Furthermore, the machine is simple in construction and is such that suflicient rail stock for a considerable number of rails may be lapped during one operation.

Although the invention has been described in connection with a certain specific structural embodiment, it is to be understood that various modifications and alternative structure may be resorted to without departing from the scope of the invention as defined in the appended claims.

I claim:

1. A machine for finishing the peripheral surface of rail stock, comprising a spindle for rotatably supporting the stock, drive means for said spindle, a shoe for applying grinding compound to the stock with a rubbing pressure, a pivotally supported arm connected to said shoe for movably supporting the same, means driven by said drive means and connected to said arm for reciprocating the shoe substantially longitudinally with respect to said spindle, and pivotally mounted pressure applying means connected to said arm for selectively moving said shoe toward and away from said spindle and holding said shoe in pressing contact with said peripheral surface while the shoe is reciprocated.

2. A machine for finishing the peripheral surface of rail stock, comprising a spindle for rotatably supporting the stock, drive means for said spindle, a shoe for applying grinding compound to the stock with a rubbing pressure, an elongated arm universally connected at one end to said shoe and universally supported at its other end, crank means driven by said drive means, a connecting rod pivotally connecting said crank means and said elongated arm for reciprocating said shoe, and pressure applying means connected to said elongated arm for bolding said shoe in pressing contact with said peripheral surface.

3. A machine for finishing the peripheral surface of rail stock, comprising a spindle for rotatably supporting the stock, drive means for said spindle, a shoe, movable support means for said shoe, reciprocating means connected to said support means and driven by said drive means for effecting reciprocation of said shoe substantially longitudinally with respect to said spindle, and pressure applying means pivotally connected to said support means for selectively moving said shoe toward and away from said spindle and for pressing said shoe in rubbing contact with said peripheral surface, said support means being mounted on a universal joint connector opposite said shoe to accommodate movement of said support means due to said pressure applying means and said reciprocating means.

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